Medical care providers recognize the need to provide warmth and cooling directly to patients as part of their treatment and therapy. For example, anesthetic properties have been reported using cold therapy for dermatology patients.
Conventional cooling technology typically includes passive cooling systems, compressor-based systems, and thermoelectric systems. In certain passive cooling systems, the air to be cooled is circulated over an air-to-air heat exchanger, which includes folded, finned heat exchangers, heat pipes, etc. The heat is then exchanged with the outside ambient air. As the amount of heat to be removed from the area increases, the size of the air-to-air heat exchanger increases. Compressor-based systems function by using a refrigerant and the cooling function is achieved by the compression and expansion of the refrigerant. Disadvantages of compressor-based systems include unwanted noise and vibration.
Thermoelectric temperature control systems use thermoelectric devices that pump heat using the Peltier effect. Typical thermoelectric devices incorporate a thermoelectric component utilizing electrical current to absorb heat from one side of the component and dissipate that heat on the opposite side. Thermal electric temperature control systems using thermal electric devices are, as described above, capable of both heating and cooling, low vibration, relatively high Coefficient Of Performance (ability to remove heat), low noise, and low profile.
It is known that dermal cooling may provide an analgesic effect such as a numbing of the surface of the skin to diminish pain caused by dermal procedures, such as, for example, laser or light-treatments and injections. To provide an analgesic effect by cooling a skin area, some approaches include the use of a cool object. Often the object is a piece of metal which has been placed first into a cooling medium, for example, a freezer or an ice bath before its use. Once the object has become sufficiently cold, the object may be removed from the cooling medium and placed on the skin surface to provide an analgesic effect. Such approaches have disadvantages. If these objects are cooled to temperatures below freezing to allow them to maintain temperatures below ambient for longer periods of time, problems may result from improper use. For example, one problem that may arise when temperatures below freezing are applied to a skin area is that cellular damage may occur.
Medical care providers thus recognize the need to provide carefully selected warmth and/or cooling directly to patients as part of their treatment and therapy. For example, anesthetic properties have been reported using cold therapy for dermatology patients. Several devices have been developed that deliver temperature controlled fluids and gasses to achieve various benefits. Typically, these devices have a heating or a cooling element, a pump for causing the air or fluid to flow, and a thermal interface between the patient and the temperature controlled fluid.
Other methods for cooling the temperature of a surface have been developed such as a roller with a cooling substance contained therein. Other pain management devices have used cooling devices that have a handle and a cooling head, where the handle contains a cooling substance to cool the head as it contacts a surface. Both pre-procedure and post-procedure dermal cooling has been utilized to protect the skin from damage from light sources used during such procedures as laser hair removal and skin peeling.